Keyed gear assembly



' R. T. HAZELTON.

KEYED GEAR ASSEMBLY.

APPLICATION FILED APR. 15. 1919.

Patented Dec. 5, 1922.

2 SHEETSSHEE'1 1.

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ATTORNEY By flaw 1 1 R. T. HAZELTON.

KEYED GEAR ASSEMBLY.

APPLICATION FILED APR. 15. 1919.

Patented Dec.

5, 1922. 2 SHEETS-SHEET 2.

4 TTOR/VEV Patented Dec. 5, 1922.

ROBERT T. HAZELTON, OF CINCINNATI, OHIO, ASSIGNOR TO THE CINCINNATI MILLING MACHINE COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO.

KEYED GEAR ASSEMBLY.

Application filed April 15, 1919. Serial No. 290,204.

To' all whom it may concern:

Be it known that I, ROBERT T. HAZELTON,

a citizen of the United States, and residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented a new and Improved Keyed Gear Assembly, of which the following specification is a full disclosure.

This invention relates to a composite gear and it proposes a construction of such a nature that it permits of being made within very accurate limits of precision and by means of conventional machine tool opera tions without difficulty.

It also proposes a construction such that the parts may be readily assembled after having been individually formed, and such that the parts will not be distorted by internal strains when assembled, and such that the driving or propelling forces between the parts will be evenly and symmetrically distributed and their action will be centralized and in balanced relation with the bearing faces or seats of the assembled members.

The practice in general vogue of fasten- I ing two members together consistsin cutting grooves in bearing faces in such amanner that they will register and form a closed groove for the reception of a key. This key is forced or driven into the groove and wedges and locks the parts together. This construction is open to the objection that the material is not only distorted and theparts are forced into eccentric relation, but also to the objection that the keys may work loose and come' out. Special forms of keys and special-methods of attaching them have been also proposed toprevent the keys from working out, but in such cases, thegdistor- 40 tion and eccentricity still remain. In certain other cases, the keys have been formed integrally with one of the members and the circumferential, regions between the keys have been cut as truly cylindrical as possible,

cutter, or by means of a grinder or cutter acting on the revolving part and caused to jump or leap over the keys to act successively on the successive bearing faces through an intermittent action. This invention proposes a construction permitting of a much greater degree of accuracy in its formation and more effective in respect to the proper interfitting of the parts. Other objects will be in part obvious from either by means of a so-called formed;-

the-annexed drawings and in part indicated in connection therewith by the following analysis of the invention.

This invention accordingly consists in the features of construction, combination of parts and in the unique relations of the members and in the relative proportioning and disposition thereof; all as more completely outlined herein.

To enable others skilled in the art so fully to comprehend the underlying features thereof that they may embody-the same by the numerous modifications in structure and relation contemplated by this invention, drawings depicting a preferred form have been annexed as a part of this disclosure, and in such drawings, like characters of reference denote corresponding parts throughout all the views, of which Fig. 1' is a vertical median section through the assembled article. Fig. 2 is a vertical section through the female gear showing its smooth, uniform recess interrupted only by grooves for receiving the keys of the male member. Fig. 3 is a side elevation of the female' gear. Fig[ 4 is a vertical section through the male member showing its two annular uninterrupted bearing surfaces and the region intermediate theretorwhich entirely clears the bore ofthe female member with the exception of the interfitting of the keys integrally radiating therefrom. Fig. 5 is an end elevation of the hub of the male member showing the' relations between the key-providing region and the two annular bearing faceslocated on its respective sides. Fig. 6 is a'plan of the hub.

This invention is exemplified by way of two gears fitted together to form a permanent unit. The one gear provides a lateral extension in the nature of a hub which enters wholly into the other gear, in a manner to be described. The interfitting is sufficiently snug and tight so as to be in the nature of a driving fit, so that the two members will, when assembled, remain permanently together without the necessity of extra fastenings. The male member, in this instance, assumes the form of a gearA having conventional teeth a and having means for mounting the same in a machine, as for example,

hub or stub-shaft; the purpose of which is of less diameter than the tips of the keys.

K, but which are of greater diameter than the segmental surfaces 7c between the various radial keys. These uninterrupted annular bearing surfaces It, Z, are finished by grinding to a high degree of precision in concentrical relation with the axis of the gear or member A. The bearing faces h, Z, preferably are somewhat narrower than the zones H and L, so as to provide slight channels k, if, Z, between the actual bearing faces and the side wall or walls adjacent the same. These channels provide clearance for the grinding wheel and insure accuracy in construction.

The complementary member, shown by Figs. 2 and 3 and indicated by A in this embodiment, is externally featured so as to provide gear teeth d This counter part member has a bore b which may be regarded as being divisible into three annular regions or zones h 70,, and Z (Fig. 2) which correspond with the surfaces h, and Z on the male member A. The intermediate zone 76,, does not serve as a contact surface, and there is an annular clearance between this region is, and the region is on the other member. The zone h however, has a snug or driving fit with the corresponding surface it on the male member, and, in like manner, the surface Z has asnug fit on the surface Z of the male member. These bearing surfaces It, h Z and Z are ground very accurately in coaxial relation, so that the female member will fit accurately on the male member. In order to accommodate the integral radial keys K, K and K the bore of the female member is provided with keyways K K and K These key-ways may be cut in the bore of the female member without in the least. impairing the concentricity of its bearing action and there is no mechanical difficulty presented by the formation of these key-ways.

In assembling, the region 11., will readily pass over the bearing surface Z, and the radial keys K, K K will enter the corresponding grooves in the female member, so that the female member may be readily forced still further over the male member until its bearing surface h registers and snugly interfits with the corresponding bearing surface it provided by. the male member. Simultaneously, the surfaces Z and Z will similarly register and interfit, so that in the ultimate article, there will be perfect accuracy in point of concent-ricity and the driving action will be balanced and symmetrically distributed, and at the same time there will be no keys to become loose, and there will be no strains distorting the members into an eccentric relation.

The formation above described admits of being very accurately and very expeditiously produced by ordinary or conventional machine tool operations. Thus, it is a simple matter to grind the bearing faces h and Z with perfect accuracy. Likewise, the successive zones is can be expeditiously milled out. by a formed cutter, as indicated by 1 in dotted lines on Fig. 5, since there is no necessity, by reason of its formation, to obtain a high dimensional accuracy in the region is. After the formed cutter 1 has embry onically produced the keys K, K and K 7 their sides are milled accurately parallel by means of the spaced millin cutters 2. If desired, the uppermost peripheries of the keys may be ground off so as to bear accurately within the complementary grooves of the female member.

It will thus be seen that this invention provides a simple solution of a difficulty that has heretofore occasioned the art considerable bother, and that, by this method, a very satisfactory assembled unit is easily and accurately derived.

Having thus revealed this invention, claim as new and desire to secure by Letters Patent of the United States 1. As a new article of manufacture, a male member providing a lateral projecting hub, said hub having equi-spaced keys integrally radiating therefrom, and having annular bearing surfaces at the ends of said keys, each of said keys being rectangular in form and having its two side-faces parallel and having its outermost peripheral face struck about a radius of greater length than the radius of either of said annular bearing surfaces; and a female member having a bore providing complementary bearing surfaces, and channels forming key-ways extending from one side snugly to accommodate said equi-spaced keys.

2. As a new article of manufacture, a-

male member providing a hub, said hub having two annular bearing surfaces spaced apart, and said hub also having a. key radiating integrally therefrom between said spaced annular surfaces; and a female mem- 3. As a new article of manufacture, a 13o male member providing a hub, said hub having symmetrically radiating therefrom a number of keys integral therewith, and having annular bearing surfaces arranged at opposite sides of said keys the bearing-surface next adjacent said member being separated therefrom by an annular channel; and a female member providing a bore presenting surfaces concentrically contacting tightly with said other two surfaces, and having channels for the snug reception of said keys.

4. A unique gear-unit comprising a first gear and a second gear having a hub later ally projecting into the bore of said first gear and having a driving-fit therein, said hub having two spaced truly cylindrical bearing-surfaces; a small number of symmetrically arranged keys located in the annular space between said separated bearingsurfaces, said keys being integral with said hub and terminating on a circle greater in diameter than the periphery of either of said bearing-surfaces, said keys being separated by segmental depressions below the periphery of each of said bearing-surfaces; the bore of said first gear providing annular seats snugly embracing said bearing-surfaces and being provided with key-ways opening into the face of said first gear nearest said second gear.

In witness whereof, I hereunto subscribe my name, as attested by the two subscribing witnesses.

ROBERT 'r. HAZELTON.

Witnesses:

K. H. WILLIAMS, Son EINSTEIN. 

